Alzheimer""s disease is a common dementing brain disorder of the elderly. The key features of the disease include progressive memory impairment, loss of language and visuospatial skills, and behavior deficits. These changes in cognitive function are the result of degeneration of neurons in the cerebral cortex, hippocampus, basal forebrain, and other regions of the brain. Neuropathological analyses of postmortem Alzheimer""s diseased brains consistently reveal the presence of large numbers of neurofibrillary tangles in degenerated neurons and neuritic plaques in the extracellular space and in the walls of the cerebral microvasculature. The neurofibrillary tangles are composed of bundles of paired helical filaments containing hyperphosphorylated tau protein (Lee, V. M and Trojanowski, J. Q, The disordered Cytoskeleton in Alzheimer""s disease, Curr. Opin. Neurobiol. 2:653 (1992)). The neuritic plaques consist of deposits of proteinaceous material surrounding an amyloid core (Selkoe, D. J., xe2x80x9cNormal and abnormal biology of the xcex2-amyloid precursor proteinxe2x80x9d, Annu. Rev. Neurosci. 17:489-517 (1994)).
Evidence suggests that deposition of amyloid-xcex2 peptide (Axcex2) plays a significant role in the etiology of Alzheimer""s disease. A portion of this evidence is based upon studies which have been generated from data with regard to familial Alzheimer""s disease. To date, this aggressive form of Alzheimer""s disease has been shown to be caused by missense mutations in (at least) three genes: the amyloid precursor protein (APP) gene itself (Goate, A. et al., xe2x80x9cSegregation of a missense mutation in the amyloid precursor protein gene with familial Alzheimer""s diseasexe2x80x9d, Nature 349:704-706 (1991) and Mullan, M. et al., xe2x80x9cA pathogenic mutation for probable Alzheimer""s disease in the APP gene at the N-terminus of xcex2-amyloidxe2x80x9d, Nature Genet. 1:345-347 (1992)), and two genes termed presenilins 1 and 2 (Sherrington, R. et al., xe2x80x9cCloning of a gene bearing missense mutations in early-onset familial Alzheimer""s diseasexe2x80x9d, Nature 375:754-760 (1995) and Rogaev, E. I. et al., xe2x80x9cFamilial Alzheimer""s disease in kindreds with missense mutations in a gene on chromosome 1 related to the Alzheimer""s disease type 3 genexe2x80x9d, Nature 376:775-778 (1995)). The missense mutations in APP are located in the region of the protein where proteolytic cleavage normally occurs (see below), and expression of at least some of these mutants results in increased production of Axcex2 (Citron, M. et al., xe2x80x9cMutation of the xcex2-amyloid precursor protein in familial Alzheimer""s disease increases xcex2-amyloid productionxe2x80x9d, Nature 360:672-674 (1992), Cai, X-D. et al., xe2x80x9cRelease of excess amyloid xcex2 protein from a mutant amyloid xcex2 protein precursorxe2x80x9d, Science 259:514-516 (1993) and Reaume, A. G. et al., xe2x80x9cEnhanced amyloidogenic processing of the beta-amyloid precursor protein in gene-targeted mice bearing the Swedish familial Alzheimer""s disease mutations and a humanized Axcex2 sequencexe2x80x9d, J Biol. Chem. 271:23380-23388 (1996)). Initial analyses of the structure of the presenilins did not suggest whether or not they might alter production of Axcex2, however, recent data has indicated that these mutations cause an increase in Axcex2 secretion (Martins, R. N. et al., xe2x80x9cHigh levels of amyloid-xcex2 protein from S182 (Glu246) familial Alzheimer""s cellsxe2x80x9d, 7:217-220 (1995) and Scheuner, D. et al., xe2x80x9cSecreted amyloid beta-protein similar to that in the senile plaques of Alzheimer""s disease is increased in vivo by presenilin 1 and 2 and APP mutations linked to familial Alzheimer""s diseasexe2x80x9d, Nature Medicine 2:864-870 (1996); Borchelt DR, et al., xe2x80x9cFamilial Alzheimer""s disease-linked presenilin 1 variants elevate Axcex21-42/1-40 ratio in vitro and in vivo,xe2x80x9d Neuron 17:1005-1013 (1996); Duff et al., xe2x80x9cIncreased amyloid-xcex242(43) in brains of mice expressing mutant presenilin 1,xe2x80x9d Nature 383:710-713 (1996); Scheuner et al., xe2x80x9cSecreted amyloid xcex2-protein similar to that in the senile plaques of Alzheimer""s disease is increased in vivo by the presenilin 1 and 2 and APP mutations linked to familial Alzheimer""s disease,xe2x80x9d Nature 2:864-870 (1996); Citron et al., xe2x80x9cMutant presenilins of Alzheimer""s disease increase production of 42-residue amyloid xcex2-protein in both transfected cells and transgenic mice,xe2x80x9d Nature Medicine 3:67-72 (1997). Tomita et al., xe2x80x9cThe presenilin 2 mutation (N141) linked to familial Alzheimer disease (Volga German families) increases the secretion of amyloid xcex2 protein ending at the 42nd (or 43rd) residuexe2x80x9d Proc Natl Acad Sci USA 94:2025-2030 (1997)). Thus, increased production of Axcex2 is associated with Alzheimer""s disease. Corroborating evidence has been derived from at least two other sources. The first is that transgenic mice which express altered APP genes exhibit neuritic plaques and age-dependent memory deficits (Games, D. et al., xe2x80x9cAlzheimer-type neuropathology in transgenic mice overexpressing V717F xcex2-amyloid precursor proteinxe2x80x9d, Nature 373:523-525 (1995); Masliah, E. et al., xe2x80x9cComparison of neurodegenerative pathology in transgenic mice overexpressing V717F xcex2-amyloid precursor protein and Alzheimer""s diseasexe2x80x9d, J Neurosci. 16:5795-5811 (1996); Hsiao, K. et al., xe2x80x9cCorrelative memory deficits, Axcex2 elevation, and amyloid plaques in transgenic micexe2x80x9d, Science 274:99-103 (1996); Sturchler-Pierrat et al., xe2x80x9cTwo amyloid precursor protein transgenic mouse models with Alzheimer disease-like pathology,xe2x80x9cProc Natl Acad Sci USA 94:13287-13292 (1997)). The second piece of evidence comes from study of patients suffering from Down""s syndrome, who develop amyloid plaques and other symptoms of Alzheimer""s disease at an early age (Mann, D. M. A. and M. M. Esiri, xe2x80x9cThe pattern of acquisition of plaques and tangles in the brains of patients under 50 years of age with Down""s syndromexe2x80x9d, J Neurol. Sci. 89:169-179 (1989)). Because the APP gene is found on chromosome 21, it has been hypothesized that the increased gene dosage which results from the extra copy of this chromosome accounts for the early appearance of amyloid plaques (Kang, J. et al., xe2x80x9cThe precursor protein of Alzheimer""s disease amyloid A4 protein resembles a cell-surface receptorxe2x80x9d, Nature 325:733-736 (1987); Tanzi, R. E. et al., xe2x80x9cAmyloid xcex2 protein gene: cDNA, mRNA distribution and genetic linkage near the Alzheimer locusxe2x80x9d, Science 235:880-884 (1987)). Taken together with the evidence derived from cases of familial Alzheimer""s disease, the current data suggests that genetic alterations which result in an increase in Axcex2 production can induce Alzheimer""s disease.
At present, less is understood about molecular modifications which are associated with the more common, sporadic form of Alzheimer""s disease. It is well-established that allelic variation of apolipoprotein E is highly correlated with expression of Alzheimer""s disease (Poirier, J., xe2x80x9cApolipoprotein E in animal models of CNS injury and in Alzheimer""s diseasexe2x80x9d, Trends Neurosci. 17:525-530 (1994); Roses, A. D. xe2x80x9cPerspective on the metabolism of apolipoprotein E and the Alzheimer diseasesxe2x80x9d, Exp. Neurol. 132:149-156 (1995)), but the mechanistic implications of this finding remain elusive. As in familial Alzheimer""s disease (Suzuki, N. et al., xe2x80x9cAn increased percentage of long amyloid xcex2 protein secreted by familial amyloid xcex2 protein precursor (xcex2APP717) mutantsxe2x80x9d, Science 264:1336-1340 (1994)) and Down""s syndrome (Teller, J. K. et al., xe2x80x9cPresence of soluble amyloid xcex2-peptide precedes amyloid plaque formation in Down""s syndromexe2x80x9d, Nature Medicine 2:93-95 (1996)), Axcex2 deposited in sporadic Alzheimer""s disease plaques is typically a longer 42 amino acid version, Axcex242 (Gravina, S. A. et al., xe2x80x9cAmyloid beta protein (A beta) in Alzheimer""s disease brain: Biochemical and immunocytochemical analysis with antibodies specific for forms ending at A beta 40 or A beta 42xe2x80x9d, J Biol. Chem. 270:7013-7016 (1995)). The suggestion that Axcex242 is particularly pathogenic is consistent with data which demonstrate that this isoform is more lipophilic, aggregates more easily, and is more neurotoxic than its 40 amino acid cousin Axcex240 (Yankner, B. A., xe2x80x9cMechanisms of neuronal degeneration in Alzheimer""s diseasexe2x80x9d, Neuron 16:921-932 (1996)). The Axcex242 phenotypic similarity gives support to the hypothesis that sporadic Alzheimer""s disease is also due to increased production of Axcex2. What remains unclear is what the nature of the change is in sporadic Alzheimer""s diseased brains which lead to increased production of Axcex2. However, because Axcex2 deposition is an early and invariant event in Alzheimer""s disease, it is believed that treatment which reduces production of Axcex2 will be useful in the treatment of this disease.
In addition to Alzheimer""s disease, amyloidosis is also implicated in the pathophysiology of both stroke and head trauma. It is well established that neuronal trauma initiated either by cerebral ischemia such as that seen in stroke and head trauma all increase expression of APP and production of Axcex2 (Siman et al., xe2x80x9cExpression of xcex2-amyloid precursor protein in reactive astrocytes following neuronal damage.xe2x80x9d Neuron 3:275-285 (1989).; Abe et al., xe2x80x9cSelective induction of kunitz-type protease inhibitor domain-containing amyloid precursor protein mRNA after persistent focal ischemia in rat cerebral cortex.xe2x80x9d Neurosci Lett 125:172-174 (1991).; Roberts et al., xe2x80x9cxcex2-A4 amyloid protein deposition in brain after head trauma.xe2x80x9d Lancet 338:1422-1423 (1991).; Gentleman et al., xe2x80x9cxcex2-Amyloid precursor protein (xcex2APP) as a marker for axonal injury after head injury.xe2x80x9d Neurosci Lett 160:139-144 (1993); Yokota et al., xe2x80x9cCytotoxic fragment of amyloid precursor protein accumulates in hippocampus after global forebrain ischemia,xe2x80x9d J Cereb Blood Flow Metab 16:1219-1223 (1996)). Indeed, the syndrome of dementia pugilistica which had been distinguished from Alzheimer""s disease because of the absence of congophilic plaques (Corsellis et al., xe2x80x9cThe aftermath of boxing.xe2x80x9d Psychological Med 3:270-303 (1973)) has been shown to be characterized by large numbers of Axcex2 containing diffuse plaques (Roberts et al., xe2x80x9cThe occult aftermath of boxing, J Neurol Neurosurg Psychiatry 53:373-378(1990)). Moreover, cerebral amyloid angiopathy is a common feature of the brains of stroke patients with symptoms of dementia, focal neurological syndromes, or other signs of brain damage (Corio and Rubio, xe2x80x9cCerebral amyloid angiopathiesxe2x80x9d, Neuropath Appl Neurobiol 22:216-227 (1996)). Taken together, these data suggest that production and deposition of Axcex2 may contribute to the pathology of Alzheimer""s disease, head injury, and stroke.
A large body of data has accumulated regarding the production and deposition of both APP and Axcex2. APP is an ubiquitous transmembrane glycoprotein (Selkoe, D. J., xe2x80x9cNormal and abnormal biology of the xcex2-amyloid precursor proteinxe2x80x9d, Annu. Rev. Neurosci. 17:489-517 (1994)). Three major isoforms of APP are produced by alternative splicing: 751 and 770 amino acid isoforms contain a Kunitz protease inhibitor domain and are expressed both in neuronal and non-neuronal cells, while a 695 amino acid isoform lacks this domain and is expressed at high levels in neurons. Mature APP is turned over rapidly, with a half life of xcx9c20-30 minutes. Embedded within the protein is a sequence of 39-43 amino acids which corresponds to the Axcex2 peptide.
Proteolytic processing of APP yields peptide fragments of varying size. An extensively studied degradative pathway is one in which the APP molecule is cleaved within the Axcex2 sequence (between residues 16 and 17) by a yet-to-be identified enzyme termed xcex1-secretase. The resultant xcx9c110-125 kDa soluble extracellular derivative termed APPS is rapidly released into the extracellular medium of cultured cells (Weidemann, A. et al., xe2x80x9cIdentification, biogenesis, and localization of precursors of Alzheimer""s disease A4 amyloid proteinxe2x80x9d, Cell 57:115-126 (1989); Esch, F. S. et al., xe2x80x9cCleavage of amyloid xcex2 peptide during constitutive processing of its precursorxe2x80x9d, Science 248:1122-1124 (1990); Sisodia S. S. et al., xe2x80x9cEvidence that xcex2-amyloid protein in Alzheimer""s disease is not derived by normal processingxe2x80x9d, Science 248:492-495 (1990)); it is estimated that xcx9c20% of the APP found on the membrane surface is released within 10 minutes (Koo, E. H. and S. L. Squazzo, xe2x80x9cEvidence that production and release of amyloid xcex2-protein involves the endocytic pathwayxe2x80x9d, J Biol. Chem. 109:991-998 (1996)). Of particular significance is the fact that this constitutively active xcex1-secretory pathway precludes the formation of intact Axcex2 and, presumably, amyloid deposition.
The Axcex2 peptide is secreted by cells (Haass, C. et al., xe2x80x9cAmyloid xcex2-peptide is produced by cultured cells during normal metabolismxe2x80x9d, Nature 359:322-325 (1992); Seubert, P. et al., xe2x80x9cIsolation and quantitation of soluble Alzheimer xcex2-peptide from biological fluidsxe2x80x9d, Nature 359:325-357 (1992); Shoji, M. et al., xe2x80x9cProduction of the Alzheimer amyloid xcex2 protein by normal and proteolytic processingxe2x80x9d, Science 258:126-129 (1992); Busciglio, J. et al., xe2x80x9cGeneration of xcex2-amyloid in the secretory pathway in neuronal and nonneuronal cellsxe2x80x9d, Proc. Natl. Acad Sci. USA 90:2092-2096 (1993)). It is believed that secreted Axcex2 contributes to the deposition of insoluble amyloid in neuritic plaques (Selkoe, D. J., xe2x80x9cNormal and abnormal biology of the xcex2-amyloid precursor proteinxe2x80x9d, Annu. Rev. Neurosci. 17:489-517 (1994)). Alternatively, Axcex2 may accumulate intracellularly and thereby initiate the disease process (Wild-Bode et al., xe2x80x9cIntracellular generation and accumulation of amyloid xcex2-peptide terminating at amino acid 42.xe2x80x9d J. Biol. Chem. 272:16085-16088 (1997)). As a result, considerable-effort is underway to unravel the molecular pathways mediating Axcex2 secretion. It appears that Axcex2 can be generated both via a classical secretory pathway (Dyrks, T. et al., xe2x80x9cAmyloid precursor protein secretion and xcex2A4 amyloid generation are not mutually exclusivexe2x80x9d, FEBS Lett. 349:210-214 (1994); Busciglio, J. et al., xe2x80x9cGeneration of xcex2-amyloid in the secretory pathway in neuronal and nonneuronal cellsxe2x80x9d, Proc. Natl. Acad. Sci. USA 90:2092-2096 (1993); Citron, M. et al., xe2x80x9cGeneration of amyloid xcex2 protein from its precursor is sequence specificxe2x80x9d, Neuron 14:662-670 (1995); Perez, R. G. et al., xe2x80x9cEnhanced release of amyloid xcex2-protein from codon 670/671 xe2x80x9cSwedishxe2x80x9d mutant xcex2-amyloid precursor protein occurs in both secretory and endocytic pathwaysxe2x80x9d, J Biol. Chem. 271:9100-9107 (1996)), and after endocytosis of APP (Koo, E. H. and S. L. Squazzo, xe2x80x9cEvidence that production and release of amyloid xcex2-protein involves the endocytic pathwayxe2x80x9d, J Biol. Chem. 109:991-998 (1996); Higaki, J. et al., xe2x80x9cInhibition of xcex2-amyloid formation identifies proteolytic precursors and subcellular site of catabolismxe2x80x9d, Neuron 14:651-659 (1995); Perez, R. G. et al., xe2x80x9cEnhanced release of amyloid xcex2-protein from codon 670/671 xe2x80x9cSwedishxe2x80x9d mutant xcex2-amyloid precursor protein occurs in both secretory and endocytic pathwaysxe2x80x9d, J Biol. Chem. 271:9100-9107 (1996)); however, many unknown details remain. Among these details is the mechanism by which Axcex2 exits the cell.
Although secretion of both APPS and Axcex2 is constitutive, the rate at which these two molecules are released from cells can be modified by activation of first and second messenger systems. APPS secretion is increased (Buxbaum, J. D. et al., xe2x80x9cProcessing of Alzheimer xcex2/A4 amyloid precursor protein: Modulation by agents that regulate protein phosphorylationxe2x80x9d, Proc. Natl. Acad. Sci. USA 87:6003-6006 (1990); Caporaso, G. L. et al., xe2x80x9cProtein phosphorylation regulates secretion of Alzheimer xcex2/A4 amyloid precursor proteinxe2x80x9d, Proc. Natl. Acad. Sci. USA 89:3055-3059 (1992); Slack, B. E. et al., xe2x80x9cRegulation by phorbol esters of amyloid precursor protein release from Swiss 3T3 fibroblasts overexpressing protein kinase Cxcex1xe2x80x9d, J Biol. Chem. 268:21097-21101 (1993); Mills, J. and P. B. Reiner, xe2x80x9cPhorbol esters but not the cholinergic agonists oxotremorine-M and carbachol increase release of the amyloid precursor protein in cultured rat cortical neuronsxe2x80x9d, J Neurochem. 67:1511-1518 (1996)) and Axcex2 secretion is decreased (Buxbaum, J. D. et al., xe2x80x9cProtein phosphorylation inhibits production of Alzheimer amyloid xcex2/A4 peptidexe2x80x9d, Proc. Natl. Acad. Sci. USA 90:9195-9198 (1993); Gabuzda, D. et al., xe2x80x9cInhibition of xcex2-amyloid production by activation of protein kinase Cxe2x80x9d, J Neurochem. 61:2326-2329 (1993); Hung, A. Y. et al., xe2x80x9cActivation of protein kinase C inhibits cellular production of the amyloid xcex2-proteinxe2x80x9d, J Biol. Chem. 268:22959-22962 (1993); Jacobsen, J. S. et al., xe2x80x9cThe release of Alzheimer""s disease xcex2 amyloid peptide is reduced by phorbol treatmentxe2x80x9d, J Biol. Chem. 269:8376-8382 (1994)) by phorbol esters, presumably via activation of protein kinase C. Similar effects are seen following activation of membrane receptors thought to couple to protein kinase C (Buxbaum, J. D. et al., xe2x80x9cCholinergic agonists and interleukin 1 regulate processing and secretion of the Alzheimer xcex2/A4 amyloid protein precursorxe2x80x9d, Proc. Natl. Acad. Sci. USA 89:10075-10078 (1992); Nitsch, R. M. et al., xe2x80x9c5-HT2a and 5-HT2c receptors stimulate amyloid precursor protein ectodomain secretionxe2x80x9d, J Biol. Chem. 271:4188-4194 (1996); Nitsch, R. M. et al., xe2x80x9cRelease of Alzheimer amyloid precursor derivatives stimulated by activation of muscarinic acetylcholine receptorsxe2x80x9d, Science 258:304-307 (1992); Lee, V. M. et al., xe2x80x9cAmyloid precursor protein processing is stimulated by metabotropic glutamate receptorsxe2x80x9d, Proc. Natl. Acad. Sci. USA 92:8083-8087 (1995); Wolf, B. A. et al., xe2x80x9cMuscarinic regulation of Alzheimer""s disease amyloid precursor protein secretion and amyloid xcex2-protein production in human neuronal NT2N cellsxe2x80x9d, J Biol. Chem. 270:4916-4922 (1995), MAP kinase (Mills et al., xe2x80x9cRegulation of amyloid precursor protein catabolism involves the mitogen-activated protein kinase signal transduction pathway,xe2x80x9d J Neurosci 17:9415-9422 (1997); Desdouits-Magnen et al., xe2x80x9cRegulation of secretion of Alzheimer amyloid precursor protein by the mitogen-activated protein kinase cascade,xe2x80x9d J Neurochem 70:524-530 (1998)), as does activation of nerve growth factor receptors (Schubert, D. et al., xe2x80x9cThe regulation of amyloid xcex2 protein precursor secretion and its modulatory role in cell adhesionxe2x80x9d, Neuron 3:689-694 (1989); Fukuyama, R. et al., xe2x80x9cNerve growth factor-induced neuronal differentiation is accompanied by differential induction and localization of the amyloid precursor protein (APP) in PC12 cells and variant PC12S cellsxe2x80x9d, Mol. Brain Res. 17:17-22 (1993); Haring, R. et al., xe2x80x9cNGF promotes amyloid precursor protein secretion via muscarinic receptor activationxe2x80x9d, Biochem. Biophys. Res. Comm. 213:15-23 (1995)) and increasing intracellular calcium (Buxbaum, J. D. et al., xe2x80x9cCalcium regulates processing of the Alzheimer amyloid protein precursor in a protein kinase C-independent mannerxe2x80x9d, Proc. Natl. Acad. Sci. USA 91:4489-4493 (1994); Querfurth, H. W. and D. J. Selkoe, xe2x80x9cCalcium ionophore increases amyloid beta peptide production by cultured cellsxe2x80x9d, Biochem. 33:4550-4561 (1994)).
In summary, Alzheimer""s disease, stroke, e.g., cerebral ischemia, and head injury are characterized by cognitive and neurological deficits associated with extracellular and cerebrovascular amyloid deposits.
This invention provides methods, compositions, and screening methods which are useful in the treatment of amyloidosis. The methods of the invention involve administering to a subject a pharmaceutical composition including one or more agents which modulate (e.g., inhibit, prevent, or enhance) production and/or release of Axcex2 and ultimately, amyloid deposition. Accordingly, the methods and compositions of the invention are useful for inhibiting amyloidosis in disorders in which amyloid deposition occurs, e.g., Alzheimer""s Disease, stroke and/or head trauma. The methods of the invention can be used therapeutically to treat amyloidosis or can be used prophylactically in a subject susceptible to amyloidosis. The methods of the invention are based, at least in part, on modulating cleavage of amyloid precursor protein (APP), the proteolytic processing of APP and/or exportation of amyloid-xcex2 protein (Axcex2) by a blocker of a member of the ATP binding cassette (ABC) superfamily of transporters expressed in the brain or the cerebral microvasculature, e.g., MDR1, MDR3, ABC1, ABC2, ABC3, ABC7, ABC8, MRP4, MRP5 or the human ABC transporters encoded by the ESTs 45597, 122234, 123147, 131042, 157481, 182763, 352188 or 422562. Therefore, a therapeutic agent, such as a blocker, used in the method of the invention can modulate amyloid deposition.
The present invention provides methods for modulating amyloid deposition in a subject, by administering to the subject an effective amount of an ATP binding cassette (ABC) transporter or flippase blocker. In one preferred embodiment, the modulation includes preventing or inhibiting the amyloid deposition. The methods provide that one or more ABC transporter blockers or flippase blockers act to antagonize transport of Axcex2 through one or more ABC transporters or flippase blockers expressed in the brain or the cerebral microvasulature.
The present invention also provides methods for treating a disease state associated with amyloid deposition by administering to a subject an effective amount of at least one ABC transporter or flippase blocker, or a pharmaceutically acceptable salt thereof, such that a disease state associated with amyloidosis is treated. In one preferred embodiment, the amyloid deposition is associated with Alzheimer""s Disease.
The present invention also provides methods for treating Alzheimer""s disease by administering to a subject having Alzheimer""s disease an effective amount of at least one ABC transporter or flippase blocker, or a pharmaceutically acceptable salt thereof, such that treatment occurs.
The present invention pertains to methods for treating head trauma by administering to a subject having head trauma an effective amount of at least one ABC transporter or flippase blocker, or a pharmaceutically acceptable salt thereof, such that treatment occurs.
The present invention also pertains to methods for treating stroke by administering to a subject affected by a stroke an effective amount of at least one ABC transporter or flippase blocker, or a pharmaceutically acceptable salt thereof, such that treatment occurs.
The present invention further pertains to packaged pharmaceutical compositions for treating amyloidosis. A packaged pharmaceutical composition includes a container which holds an effective amount of a pharmaceutical composition for modulating amyloid deposition in a subject. The pharmaceutical composition includes at least one ABC transporter or flippase blocker and instructions for using the pharmaceutical composition. In one preferred embodiment, the packaged pharmaceutical composition is for treatment associated with Alzheimer""s Disease.
The present invention also pertains to methods for identifying agents which modulate amyloid deposition in an organism by administering to an organism an effective amount of at least one ATP binding cassette (ABC) transporter or flippase blocker, such that modulation of amyloid deposition occurs. The methods provide that one or more ABC transporter blockers or flippase blockers which act to antagonize transport of Axcex2 through one or more ABC transporters or flippase blockers expressed in the brain or the cerebral microvasulature can be identified.
The present invention further pertains to methods for identifying agents which modulate transport or flipping of amyloid across a membrane, e.g., a cellular or synthetic membrane. The methods include introducing an agent into a model system containing the membrane, e.g., cellular or planar lipid membrane, ABC transporter and amyloid. The ability of the agent to modulate the transport or flipping of amyloid across the membrane is measured. The methods provide the ability to identify of one or more ABC transporter blockers or flippase blockers which act to antagonize transport of Axcex2 through one or more ABC transporters or ABC transporters having flippase activity which are expressed in the brain or the cerebral microvasulature.